Floor scrubbing machines are widely used to clean the floors of industrial and commercial buildings. They range in size from a small model which may clean a path ranging from perhaps 15 inches up to 36 inches wide controlled by an operator walking behind it, to a large model cleaning a path as wide as five feet controlled by an operator riding on the machine. In general, these machines have a wheeled chassis which contains, in addition to power and drive means, a tank to hold clean scrubbing solution and a tank to hold soiled solution recovered by a vacuum squeegee system from the floor being scrubbed. A scrub head containing one or more rotating scrub brushes and means to power them is attached to the chassis by an articulated linkage system, and may be located in front of, under or behind the chassis. Each location has certain advantages and disadvantages.
Thus a scrub head located in front of the chassis can reach into corners and clean them more completely than one mounted under or behind the chassis. However, it is more vulnerable to being damaged by collisions with fixed objects. This drawback has typically been addressed by providing such machines with heavy protective shrouds or bumpers either attached to the scrub head or attached to the chassis and made to overhang the scrub head. Some of these layouts interfere with the reach or effectiveness of the head, complicate serviceability, and add weight and cost. On such machines there is a need for a way to protect the scrub head from collision damage without using protective shrouds or heavy bumpers.